Controlled variable pitch propeller



March 28, 1939. B. B. GEMENY v CONTROLLED VARIABLE PITCH PROPELLER Filed July 30, 1935 4 Sheets-Sheet l blazne QGemerig,

March 28, 1939. B. B. GEMENY CONTROLLED VARIABLE PITCH PROPELLER Filed July 30, 1935 4 Sneets-Sheet 2 March 28, 1939. B. a. GEMENY CONTROLLED VARIABLE PITCH PROPELLER Filed July 30, 1935 4 Sheets-Sheet 3 blazrzeb. Gemerz y, A

March 28, 1939. B. B. GEMENY 2,152,587

CONTROLLED VARIABLE PITCH PROPELLER Filed July 30, 1955 4 Sheets-Sheet 4 gwuc Mom [Hal/2e 5 Game/2y 55, not being operated.

Patented Mar. 28, 1939 UNITED STATES 2,152,587 CONTROLLED VARIABLE PITCH PROPELLER Blaine B. Gemeny, Washington, D. 0., assignor of one-third to Earle D. Crammond, Washington, D. 0.

Application July 30,

9 Claims.

The invention relates to improvements in controlled variable pitch propellers, and to mechanical means for varying the pitch of such propellers. More particularly, the invention relates to propellers for air craft whereln'the blades of the propeller are rotatably mounted in a hub to provide for variation of the blade angles automatically in response to load and operating conditions and in response to manual control.

This application is in part a continuation of my copending application Serial No. 711,245, filed February 14, 1934, now Patent No. 2,030,953, which describes an automatic variable pitch propeller wherein the centrifugal forces otherwise tending to turn the blades during operation of the propeller are balanced out and the air forces acting on the blades during their operation are utilized and controlled to automatically vary the pitch of the propeller to obtain an efiicient angle of attack in direct accordance with engine speed, speed of the plane and wind velocities. peller of the copending application referred to is specifically an automatically operative device.

whereas the structure of this invention permits fine tuning and is arranged for auxiliary manual, control while still retaining automatic characteristics of operation.

It is one of the objects of this invention to provide a variable pitch propeller wherein all of the blades are synchronized in their control, and in which the centrifugal forces acting on the blades during operation of the propeller are balanced out so that the angle of attack may be automatically varied in direct response to air forces acting on the blades while the propeller is in operation.

Another .Qbjective is the provision of a propeller permitting manual adjustment of the blade angles, for finer tuning and adjustment of the blade angles by an operator during rotation of the propeller.

A further object of the invention is to provide means for varying the pitch of a variable pitch propeller while it is rotating without materially affecting rotational speed of the propeller. It is also an object of the invention to effect variation of the pitch of the propeller by mechanical means, either manually or power-operated, in a relatively fixed position on a vehicle with respect to the rotating driving shaft and propeller. It is a further object of the invention to pro- .vide means for varying the automatic operating "range of an automatic variable pitch propeller,

either when the propeller is in use or when it is The pro- I 1935, Serial No. 3339a (01. 170-162) Further objects and advantages of the invention will be apparent from the detailed description embodied in the following specification and by reference to the drawings referred to therein.

In the drawings, like reference numerals represent like parts throughout the several figures, and

Fig. 1 shows a central longitudinal sectional 3, showing a modified form of adjustment member to provide a variable spring adjustment.

Fig. 7 is a rear plan view of the control connections for the propeller of Fig. 1.

Fig. 8 is a rear plan view of the control members for a modified form of propeller having three blades.

Fig. 9 is a plan view of the control members of a modified form of propeller having four blades.

Fig. 10 is a side view partly in section showing a modified mechanical control arrangement.

Fig. 11 is a vertical sectional view of a manual control lever for the device of Fig. 10.

Fig. 12 is a front elevation view of the device of Fig. 10.

Fig. 13 is a sectional view on the line I3|3 of Fig. 10. I

Fig. 14 is a top plan view of the hand control of Fi 11.

Referring in particular to Figs. 1 and 3 of the drawings, numeral 1 indicates a propeller embodying features of the invention mounted on driving shaft 2 of a. driving motor 3 for an air craft or other vehicle. The propeller consists of a hub 4 having a plurality of radially extending supporting housings or sockets 5 for supporting the inner ends of rotatably mounted blades 6. The propeller illustrated in Figs. 1 to 3 of the drawings is of the two-blade type similar to that described in my copending application Serial No. 711,245, now U. S. Patent 2,030,953 but it is to be understood that the invention is inclusive of propeller structures having more than two blades such as described in my copending application Serial No. 59,967, filed January 20, 1936, and to other forms of propellers.

The hub of the propeller consists of metal sections clamped together by through bolts land clamping rings 8 surrounding the ends of the blade holding radial extensions. The metal sections of the hub are provided in each of the radial extensions with cooperating inwardly directed flanges 9, outwardly facing shoulders Ill and recesses II, with the flanges 9 and shoulders II! defining recesses to receive bearing assemblies for supporting the blades so that the hub sections in assembled relationship serve to clamp in position the bearing assemblies and a movable annular adjustment and'abutment member l2. The bearing assemblies and means for retaining the blades in the hub are identical with those described'in my copending application Serial No. 711,245, filed February 14, 1934, now U. S. Pate ent No. 2,030,953, and in brief, comprise for each blade member an axialthrust anti-friction bearing assembly l3 between the inwardly facing surface of fiange 9 and a cooperating surface of an adjustable collar member l4 adjustably connected with the blade shank. This arrangement retains each blade in the hub and the axial thrust bearing assumes the entire outward thrust of the blade when the propeller is rotated. A radial thrust anti-friction bearing I5 is adjustably positioned against the outwardly facing surface of the inwardly directed flange 9 by adjustable collar 18 mounted on the blade shank and a second radial "thrust anti-friction bearing I1 is p0sitioned against the outwardly facing shoulder ill surface extending therearound from opposite sides of the abutment 20. This crank collar is provided with diametrically opposite laterally extending stub shafts or supports 2| each pivotally mounting thereon weight lever arms 22 each cooperating with similar arms on an adjacent crank collar, to movably support balance weight 23. These arms and weights, by their connection with the crank lever collars fixed to the ends of I the blades for turning the blades, serve to counterbalance centrifugal forces tending to turn the 'blades when the propeller is rotated.

The crank lever collars are adjusted on each of the shanks of the blades to lie substantially in the same plane with an annular adjustment member 12 positioned for movement in a recess ll of the hub. The crank collars are held in their position of adjustment with respect to the blades by any suitable means, keys being here illustrated engaging keyways in the blade and collar.

The surfaces within the recesses and those of the adjustment member I2 are so conditioned as to minimize frictional resistance to movement of the adjustment, or, if desired, the adjustment members maybesupported in the recesses by antii'riction bearings. The adjustment members are provided in their outer periphery with teeth 25 adapted to engage with a worm gear 26 mounted in a recess in the hub onv shaft 2'1 extending through the hub and terminating at its front end in atool-engaging portion fl'and at theotherend exposed gear or gears on the propeller.

amass? in an extension 29 beyond the hub supporting thereon sprocket 30 and gear 3|, both of which are fixed to the shaft for rotation therewith. The adjustment members are also provided with an inwardly extending lug 32 and a grooved or concave inner edge surface extending therearound from opposite sides of the lug 32. A spring 33, housed between the concave surfaces on the adjustment member and the lever control member, engages at one end with the inwardly extending lug on the adjustment member and at the other end with the outwardly extending lug on the lever control member on the end of the propeller blade. By this arrangement, the rotatable blade is biased under influence-of the spring through the lever controlmember in one direction, which is that normally opposite to the diection of movement of the blade occasioned by the air forces acting on the blade when the propeller is rotated.

Each of the movable adjustment members, by their cooperation with the irreversible worm gear connection and the resilient control opposing the turning of the blades from the air forces, serve to hold the blades in a pitch adjustment determined by the position of the adjustable members and by the air forces acting on the propeller when ;the propeller is in 11584 The sprockets 30 mounted on the outside of the hub are connected by sprocket chains '10 to provide synchronizing ad justment of all of the blades when oneor the other of the worm gear shafts is rotated. Adjustment of the pitch of the propeller blades when the propeller is not in use can be accomplished by turning one of the shafts 21 by a suitable tool 00- operating with the forward end of the shaft. This arrangement allows a fine predetermined tuning of the propeller by obtaining an accurate adjustment of the blades prior to use to a predetermined pitch angle. The shafts 21 are substantially parallel to the axis of the driving shaft on which the propeller is mounted and the gear or gears 3 i, when more than one is employed, are so mounted on these shafts as to lie in a single plane and at points equidistant from the axis of the driving shaft.

To provide for adjustment of the pitch of the propeller by mechanical means when the'propeller is rotating, there is shown in Figs. 3 to 5, as mounted on the motor housing, a support member 34 which is rigidly mounted to bear a fixed position with respect to the rotating driving shaft and propeller. A train of gears 35, 36 and 31 are mounted on stub shafts anchored in the support member. The two outer gears 35 and 31 have connected therewith single toothed gears which may be mounted on the same shaft, or be made integral with the gears. toothed gears 3838 are so arranged that the teeth extend laterally from the axis of the shafts on which they are mounted in the same direction to provide alternate engagement with the gears mounted on' the worm gear shafts in the propeller. The single toothed gears are so arranged in their fixed position on the vehicle as to lie substantially in a single planeinclus-ive of the The single toothed gears are so spaced that a gear on the propeller passes therebetween in the normal operation of the device but are so arranged These single nected with the propeller control members to the extent of one tooth movement at each successive contact with a single toothed gear on the fixed control mechanism. The shaft mounting the single toothed gear 38 and cooperating gear. 35 extends through the support and, is there connected with a flexible shaft 39 extending to a position on the vehicle where its movement can be controlled by an operator of the vehicle. The flexible shaft is shown in Fig. 4 extending through a support 40 on the vehicle adjacent to which it is operatively connected with an indicating device 4| and with a. manually operable handle 42 which, when turned in either direction, will produce rotary movement of the flexible shaft and the connected gears of the gear train. The driving connection of the handle with the shaft is made with a suitable lost motion connection so that a limit-' ed relative movement of handle and shaft may be provided before positive driving engagement, in either direction, between the shaft and handle is effected. The amount of lost motion provided for in either direction, with the handle in an intermediate position, is only that suflicient to allow the single tooth gears of the fixed gear train to be pushed out of the path of the gear on the propeller when the propeller is rotated. This will also avoid any shock transmission to the hand of an operator when the handle is rotated to effect adjustment of the propeller under flight conditions. The indicator 4| may be any well known indicator structure which will indicate changes from a normal set position. This indicator may be associated with the flexible shaft to indicate the extent of rotation of the shaft in either direction in effecting changes in the adjustment of the propeller from its original adjusted position.

When the gear train is actuated by rotation of the flexible shaft during rotation of the propeller, the single toothed gears will rotate to intermittently engage gear 3| on the propeller when the single tooth of one of the gears is in the path of movement of the gear revolving with the propeller. The single tooth gear rotating in an opposite direction to the direction of travel of the gear on the propeller will move the propeller gear each time it is brought into engagement with the passing gear. The lost motion connection between the handle and shaft will allow the other single tooth gear to move out of the path of the revolving propeller gear. thus compensating for relatively different rotational speeds without shock to the operator. The lost motion connection between the handle and the shaft may be of any conventional type resilient or otherwise in accordance with practices well known in the art. Double ratchet connections may also be employed in a manner well known in the art to provide relative movement between the handle and the shaft. The gears mounted on the propeller adjusting shaft are illustrated as having thirtythree teeth and one complete revolution of these gears creates an angular shift of the adjustment members within the propeller hub a distance equivalent to one tooth of the worm gear connection with the adjustment members. It will thus be observed that the adjustment of the propeller by an operator when it is rotated will constitute a very gradual adjustment. This adjustment may be obtained in either direction dependent upon the direction of rotation of the gear train in the flxed position on the vehicle. It will be further noted in connection with the arrangement just described that the'e ngagement of the gearswon the propeller with the single toothed gears on the fixed gear train is intermittent and of insufficient duration to materially affect the speed of rotation of the propeller. The single toothed gears on the gear train will be automatically pushed out of the path of the gears on the propeller when the gear train is not being operated to effect a propeller adjustment, thus leavthat is necessary, but it will be understood that if faster adjustment is desired, gears may be provided on all of the worm gear adjustment shafts so that as ear gear passes through the position adjacent the fixed gear trains, it may be operated to procure a further adjusted movement of the blades of the propeller.

In the modified showings of Figs. 7, 8 and 9, the continuous sprocket chain 10 is shown in engagement with each of the sprockets so that when the gear 3| is rotated in either direction, the rotation is conveyed simultaneously to produce movement of the remaining shafts and worm shafts to effect identical movement of the adjustment members l2 within the hub of the propeller. It will be appreciated by those skilled in the art that the fixed gear train for cooperation with the gears on the propeller may be rotated by power, connections withthe shaft of the driving motor or by separate power means, if desired, in place of the manual adjustment selected for illustrated purposes.

Referring now to Figs. 10 to 14, inclusive, of thedrawings, there is shown a modified form of mechanical adjusting means which may be mounted in fixed position on the air craft or othervehicle to be used at the will of an operator to effect adjustment of a variable pitch propeller during its operation; This modified form of control is arranged for cooperation with an element revolving with the propeller. Thiselement is shown as gear 3| of the propeller adjustment mechanism which has been previously described. The adjustment structure within the propeller being unchanged, reference is had to' ends to support oppositely disposed bearing members 49 of rubber or other resilient members. A gear engaging contact element 45 is pivotally mounted in the bearings by trunnions 48 and has at its opposite ends angular projections 46 so conformed as to releasably engage between adjacent teeth of the gear 3|. The angular projections may be formed as integral parts of the member ormay be made of sound deadening material connected to the pivoted member but spaced from each "other a suflicient distance to allow passage of the gear 3| therebetween without contact when the control element is in its normal or inoperative position. This normaliposition of the control element is maintained by leaf spring mounted on the support and having free ends of the spring in engagement with the control element on opposite sides of the point of'its pivotal support in the bracket.

Means are provided for rocking the gear engaging element in either direction against the tension of one end of the leaf spring to cause one or the other of the angular teeth engaging projections to move into the path of the gear 3! on the rotating propeller to obtain a progressive rotation of the gear, thus effecting adjustment of the pitch of the propeller blades in one direction or the other. A bracket 52 having spaced supporting arms may be positioned within reach of an operator and carries a pivoted handle or lever 53 provided with spaced stop lugs 55 cooperating with a stop 56 on the bracket to limit the movement of the handle. Wires or other members 59 serve to connect lugs 51 and 58 on the hand lever with the gear engaging element of lugs 41 on opposite sides of their respective pivots so that movement of the handle lever in either direction from its normal position, which corresponds to the normal position of the gear engaging element, will cause one or the other of the angular projections to move into the path of the gear 3! on the rotating propeller.

In operation of the control to decrease or increase the pitch of the propeller, it is only necessary to move the hand lever from the neutral position in one or the other directions as the case may be, and the gear on the propeller by its intermittent engagement with the gear contacting element, will progressively rotate to effect adjustment of the propeller pitch. When the hand lever is released it will return to its neutral position under influence of spring 50, assisted by the gear which will tend to push the gear engaging element into a neutral position when not opposed by pressure on the hand lever. In case an operator should, in error, extend adjustmentv to the limit in either direction, no harm will result because of the inherent resiliency of the anism is accomplished through the entire propeller mechanism in connection with the blades. 'I 'his preferred form of illustration is not to be taken, however, as limiting application of the mechanical control features for it will be obvious to those skilled in the art that this control may be used in propeller structures employing rigid connections between the blade shank and an element moved by the worm gear.

In using spring pressure for cooperation with air forces to adjust the propeller blade angle; the

spring pressure varies substantially in a definite ratio to the amount the spring is compressed.

.In'some cases, due to body design and other factors this variation may not be in exact relation to the air forces at all positions and it may "be desirable toregulate spring pressure to balance the force; ;This may be accomplished by .va-rying the leverage in the manner illustrated v fin-@553. 6. of; the drawings. The movable abutme'nt member ii' is shown having its inner diamamass:

eter gradually increased adjacent the inwardly extending lug 32 and thespring 33 is provided with the spherical headed member 69 which forms the contact point of the spring against the lug 2n and the inner surface of the abutment member. The leverage is allowed to vary with this construction so that when the blade is in the full open position and the spring is in its position of least pressure, the leverage is maximum and when the blade is in closed position the leverage 1s a minimum. r

The advantages of the invention and the operation thereof have been made apparent from the foregoing description of the preferred form of structure selected for illustration. The intermittent contact of the control mechanism when operated with the element rotating with the propeller does not place any particular load on the propeller and does not impair normal operation thereof. Furthermore, the simple mechanical means for changing the pitch of the pro peller does not materially add to the propeller weight and obviates the use of motors, elaborate gearing and other complicated mechanism.

While the invention has been described in connection with a preferred embodiment, it is to be understood that the words which have been used are words of description rather than of limitation and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in all its aspects.

I claim:

i. In an automatic variable pitch propeller having a hub and a plurality of blades mounted for turning movement in the hub, adjusting means mounted in the hub including separate worm and gear connections to said blades and a manually operable member on the outside of the hub for varying the angle of the blades to adjust the propeller to a predetermined pitch prior to its operation, means for intermittent connection with said adjusting means for manually varying the pitch of the propeller when the propeller is being operated, and means for automatically varying the pitch of the adjusted propeller' in relation to the air forces acting on the blades when the propeller is rotated, said last mentioned means having its range of automatic variation determined by the position of adjustment of the manually'operable means.

i 2. In an automatic variable pitch propeller having a hub and a plurality of blades mounted.

for turning movement within the hub, means within the hub for automatically varying the pitch of the propeller in response to the air forces acting on the blades when the propeller is rotated, said means'including movable adjustment members each having an inwardly extending lug, an annular crank lever member attached to the end of each blade and having a radially extending lug and a spring between the lug of each crank lever member and the lug of an adjustment member exerting its force directly on said lugs, and means for moving the adjustment members to control the range of automatic operation of the propeller. V

3. In a variable pitch propeller having a hub and a plurality of blades mounted for turning movement in the hub, an annular crank lever member attached to each of theblades, means including movable weights interconnecting adjacent propeller blades to counterbalance centrifugal forces causing turning movement of blades in the hub 'whenrotated, an adjustable member cooperating with each of the crank lever ,members, yieldable means between the lever movement in the hub, an annular crank lever,

member attached to each blade and having a concave periphery and a radially extending lug, adjustable annular members each having an inwardly facingconcave surface and an inwardly extending lug, springs housed between concave surfaces and lugs on therespective annular lever members and the adjustable members. and means for controlling the position of the adjustable annular members while the propeller is being rotated to increase or decrease the compression of the springs.

5. In combination with a variable pitch pro peller having a hub and a plurality of blades mounted for turning movement therein, adjusting means mounted in the hub for varying the angle of the blades to obtain a predetermined pitch for the propeller, and separate mechanical means normally out of engagement with the adjusting means but arranged for connection therewith for varying the pitch of the propeller when the propeller is being operated, means including springs for normally maintaining the blades in their adjusted position, said last mentioned means yielding to vary the pitch of the propeller in direct relation to air forces acting on the blades when the propeller is rotated.

6. In a variable pitch propeller, a hub, a plurality of propeller blades rotatably mounted in the hub and having lever control members fixed to their inner ends for turning the blades, a plurality of movable weight mechanisms interconnecting the lever control members in series to counterbalance centrifugal forces tending to turn the blades when the propeller is rotated, resilient means opposing movement of the lever control member under the influence of air forces on the blades, means for controlling the operable force of said resilient means while the propelleris being operated, said last mentioned meansincluding irreversible gear connections to effect change of position of said members.

'7. In combination with a driving shaft and a variable pitch propeller thereon having means automatically varying the pitch of the propeller in response to air forces acting on the blades when the propeller is rotated, mechanical means for varying the operating range of said automatic variable means, said mechanical means including gearing radially positioned with respect to the driving shaft and extending on the outside of the propeller, a gear train including single toothed gears mounted on a'flxed support for intermittently engaging the gearing on the propeller when the propeller is rotated, and means including a manually operable member for actuating said gear train to cause its intermittent connection with the gearing on the propeller to control the amount of variation of the automatic means on the propeller.

8. In combination with a propeller having a hub and a plurality of blades mounted for tum-.

ing movement in the hub,'means including worm and gear connection to each blade and a member disposed outside the propeller hub for turning the blades in the hub to vary the pitch of the propeller and control mechanism mounted in relatively fixed position adjacent the propeller including an element arranged to be moved into intermittent contact with said member outside the hub to actuate said means whereby a progressive adjustment of the pitch of the propeller is obtained.

9. In combination with an air-craft'and its motor having a driving shaft, an automatic variable pitch propeller having a hub mounted on the shaft, a plurality of blades mounted for turning movement in the hub, and means within the hub for automatically controlling the pitch of the blades and counterbalancing centrifugal forces which tend to turn the blades during operation of the propeller, means for changing the range of automatic operation of said means, said last mentioned means including a gear member outside the hub of the propeller revoluble in a path surrounding the driving shaft, a :contact element mounted in relatively fixed position adjacent the path-of revolution of said gear member, and means for moving the contact element into the path of revolution of said gear member to effect intermittent contact of the element N and gear member during rotation of the propeller.

BLAINE B. GEMENY. 

